[mythtv-users] Problem with TV resolution after upgrading to 20.04

[Kenneth Emerson]

I've recently upgraded (fresh install) of Xubuntu 20.04. I'd been
using Ubuntu (desktop) for almost 10 years, but recently the gnome
desktop has been giving me fits.  I had Xubuntu on my remote frontend,
and that installation was a charm, fixing all the problems with menu
bars.

So, the installation went well with the exception of losing a power
supply in one of my disk arrays (fixed and the raid arrays are all
online) but I still have problems with the part that everyone using
the system looks at: the TV.  I set the display to 3840x2160 in the
desktop and told it to hide the menu bar and it looked great! Until I
turned the TV off and back on.  It had changed the resolution to
1920x1080.

After some digging I found the issue with X.  In the Xorg.log.0 file I
see this after switching the display to the proper resolution:

[ 52764.156] (--) NVIDIA(GPU-0): DFP-0: disconnected
[ 52764.156] (--) NVIDIA(GPU-0): DFP-0: Internal TMDS
[ 52764.156] (--) NVIDIA(GPU-0): DFP-0: 165.0 MHz maximum pixel clock
[ 52764.156] (--) NVIDIA(GPU-0):
[ 52764.186] (--) NVIDIA(GPU-0): DENON, Ltd. DENON-AVR (DFP-1): connected
[ 52764.186] (--) NVIDIA(GPU-0): DENON, Ltd. DENON-AVR (DFP-1): Internal TMDS
[ 52764.186] (--) NVIDIA(GPU-0): DENON, Ltd. DENON-AVR (DFP-1): 600.0
MHz maximum pixel clock
[ 52764.186] (--) NVIDIA(GPU-0):
[ 52764.241] (II) NVIDIA(0): Setting mode "HDMI-0: 3840x2160
@3840x2160 +0+0 {ViewPortIn=3840x2160, ViewPortOut=3840x2160+0+0}"

Then after turning the TV off I see this:

[ 52827.478] (--) NVIDIA(GPU-0): DFP-0: disconnected
[ 52827.478] (--) NVIDIA(GPU-0): DFP-0: Internal TMDS
[ 52827.478] (--) NVIDIA(GPU-0): DFP-0: 165.0 MHz maximum pixel clock
[ 52827.478] (--) NVIDIA(GPU-0):
[ 52827.508] (--) NVIDIA(GPU-0): DENON, Ltd. DENON-AVR (DFP-1): connected
[ 52827.508] (--) NVIDIA(GPU-0): DENON, Ltd. DENON-AVR (DFP-1): Internal TMDS
[ 52827.508] (--) NVIDIA(GPU-0): DENON, Ltd. DENON-AVR (DFP-1): 600.0
MHz maximum pixel clock
[ 52827.508] (--) NVIDIA(GPU-0):
[ 52827.543] (II) NVIDIA(0): Setting mode "HDMI-0: nvidia-auto-select
@1920x1080 +0+0 {ViewPortIn=1920x1080, ViewPortOut=1920x1080+0+0}"

And there it stays until I go back into the display properties and put it back.

I also noticed this declaration in the Xorg.log.0 file:

[ 52762.997] (--) NVIDIA(GPU-0): DFP-0: disconnected
[ 52762.997] (--) NVIDIA(GPU-0): DFP-0: Internal TMDS
[ 52762.997] (--) NVIDIA(GPU-0): DFP-0: 165.0 MHz maximum pixel clock
[ 52762.997] (--) NVIDIA(GPU-0):
[ 52763.027] (--) NVIDIA(GPU-0): DENON, Ltd. DENON-AVR (DFP-1): connected
[ 52763.027] (--) NVIDIA(GPU-0): DENON, Ltd. DENON-AVR (DFP-1): Internal TMDS
[ 52763.027] (--) NVIDIA(GPU-0): DENON, Ltd. DENON-AVR (DFP-1): 600.0
MHz maximum pixel clock
[ 52763.027] (--) NVIDIA(GPU-0):
[ 52763.031] (==) NVIDIA(0):
[ 52763.032] (==) NVIDIA(0): No modes were requested; the default mode
"nvidia-auto-select"
[ 52763.032] (==) NVIDIA(0):     will be used as the requested mode.
[ 52763.032] (==) NVIDIA(0):
[ 52763.032] (II) NVIDIA(0): Validated MetaModes:
[ 52763.032] (II) NVIDIA(0):     "DFP-1:nvidia-auto-select"
[ 52763.032] (II) NVIDIA(0): Virtual screen size determined to be 1920 x 1080
[ 52763.039] (--) NVIDIA(0): DPI set to (30, 30); computed from
"UseEdidDpi" X config
[ 52763.039] (--) NVIDIA(0):     option
[ 52763.039] (II) NVIDIA: Using 24576.00 MB of virtual memory for
indirect memory
[ 52763.039] (II) NVIDIA:     access.
[ 52763.059] (II) NVIDIA(0): Setting mode "DFP-1:nvidia-auto-select"

Other people with a 4K monitor must have discovered this issue, but my
searching has only shown up some older issues fixed with modelines or
insidious EDID fake files to force X not to ask for what's available.
I've tried some of these with no success, but thought someone has had
to have come across this before, so I'm humbly asking for help.

I'm using an NVIDIAGeForce GT1030 card, NVIDIA driver 450.51.06, a
Denon AVR-X2600H, and an LG OLED65C9PUA 4K HDR TV.

Regards,

Ken Emerson